Matrix on the C64 is deliberately slow. With the following simple patch we can tune it to be twice as fast, and to my taste, even more enjoyable to play.
diff --git a/src/c64/matrix.asm b/src/c64/matrix.asm
index de54195..37ea478 100644
--- a/src/c64/matrix.asm
+++ b/src/c64/matrix.asm
@@ -1000,7 +1000,7 @@ AnimateCurrentBullet
BEQ b8535
b8534 RTS
-b8535 LDA #$20
+b8535 LDA #$09
STA bulletFrameCounter
; Play Bullet Sound
@@ -1543,7 +1543,7 @@ AnimateZapperTail
ROL
ADC #$00
;FIXME: should this be charSetLocation + $0109 like in Vic20?
- STA f1509
+ STA charSetLocation + $0109
RTS
;-------------------------------------------------------------------------
@@ -1635,7 +1635,7 @@ AnimateDroidSquads
BEQ b8947
b8946 RTS
-b8947 LDA #$C0
+b8947 LDA #$60
STA droidAnimationFrameRate
JSR AnimateSnitch
LDA noOfDroidSquadsLeftInCurrentLevel